Wellbore annular safety valve and method

ABSTRACT

A well system includes an annular barrier separating the tubing-casing annulus into an upper annulus and a lower annulus and a barrier valve coupled with the annular barrier, the barrier valve permitting one-way fluid communication from the upper annulus to the lower annulus. The annular barrier may include a female polished bore receptacle integrated in the casing and a male seal assembly integrated in the tubing. The tubing bore and an annular fluid conduit extend through the male seal assembly substantially parallel to one another and the barrier valve is connected in the annular fluid conduit.

BACKGROUND

This section provides background information to facilitate a betterunderstanding of the various aspects of the disclosure. It should beunderstood that the statements in this section of this document are tobe read in this light, and not as admissions of prior art.

Hydrocarbon fluids such as oil and natural gas are obtained from asubterranean geological formation, referred to as a reservoir, bydrilling a well that penetrates the hydrocarbon-bearing formation. Formsof well completion components may be installed in the wellbore tocontrol and enhance efficiency of producing fluids from the reservoir.

SUMMARY

A well system in accordance to one or more embodiments includes anannular barrier disposed in a tubing-casing annulus of a wellboreseparating the tubing-casing annulus into an upper annulus and a lowerannulus and a barrier valve coupled with the annular barrier, thebarrier valve permitting one-way fluid communication from the upperannulus to the lower annulus. An annular safety valve in accordance withan embodiment includes a male seal assembly integrated in a tubing, atubing bore and a fluid conduit extending through the body substantiallyparallel to one another, a female polished bore receptacle integrated ina casing to receive the male seal assembly and form an annular barrierbetween the tubing and the casing, and a barrier valve in connectionwith the fluid conduit to permit one-way fluid flow through the fluidconduit. A method includes setting casing having a female polished borereceptacle in a wellbore, deploying tubing having a male seal assemblylanded in the female polished bore receptacle forming an annular barrierseparating the tubing-casing annulus into an upper annulus and a lowerannulus, communicating fluid from the upper annulus through a barriervalve in connection with a fluid conduit through the male seal assemblyand closing the barrier valve in response to pressure in the upperannulus being lower than the pressure in the lower annulus.

The foregoing has outlined some of the features and technical advantagesin order that the detailed description of the annular safety valves,systems, and methods that follow may be better understood. Additionalfeatures and advantages of the annular safety valve system and methodwill be described hereinafter which form the subject of the claims ofthe invention. This summary is not intended to identify key or essentialfeatures of the claimed subject matter, nor is it intended to be used asan aid in limiting the scope of claimed subject matter.

BRIEF DESCRIPTION OF THE DRAWINGS

Embodiments of annular safety valves and methods are described withreference to the following figures. The same numbers are used throughoutthe figures to reference like features and components. It is emphasizedthat, in accordance with standard practice in the industry, variousfeatures are not necessarily drawn to scale. In fact, the dimensions ofvarious features may be arbitrarily increased or reduced for clarity ofdiscussion.

FIG. 1 illustrates a well system in which an annular safety valve inaccordance to one or more embodiments is incorporated.

FIG. 2 illustrates an annular safety valve in accordance to one or moreembodiments.

FIG. 3 illustrates a male polished bore receptacle seal assembly inaccordance to one or more embodiments.

FIG. 4 is a top view illustration of a male polished bore receptacleseal assembly in accordance to one or more embodiments.

FIG. 5 illustrates a side pocket mandrel in accordance to one or moreembodiments.

FIG. 6 illustrates a side pocket mandrel along the line I-I of FIG. 5.

FIG. 7 illustrates a barrier valve in accordance to one or moreembodiments.

DETAILED DESCRIPTION

It is to be understood that the following disclosure provides manydifferent embodiments, or examples, for implementing different featuresof various embodiments. Specific examples of components and arrangementsare described below to simplify the disclosure. These are, of course,merely examples and are not intended to be limiting. In addition, thedisclosure may repeat reference numerals and/or letters in the variousexamples. This repetition is for the purpose of simplicity and clarityand does not in itself dictate a relationship between the variousembodiments and/or configurations discussed.

As used herein, the terms “connect,” “connection,” “connected,” “inconnection with,” and “connecting” are used to mean “in directconnection with” or “in connection with via one or more elements”; andthe term “set” is used to mean “one element” or “more than one element.”Further, the terms “couple,” “coupling,” “coupled,” “coupled together,”and “coupled with” are used to mean “directly coupled together” or“coupled together via one or more elements.” As used herein, the terms“up” and “down,” “upper” and “lower,” “top” and “bottom,” and other liketerms indicating relative positions to a given point or element areutilized to more clearly describe some elements. Commonly, these termsrelate to a reference point as the surface from which drillingoperations are initiated as being the top point and the total depthbeing the lowest point, wherein the well (e.g., wellbore, borehole) isvertical, horizontal or slanted relative to the surface.

Generally, a well consists of a wellbore drilled through one or morereservoir production zones. Conductor casing serves as support duringdrilling operations and provides support for a wellhead and Christmastree. In offshore wells, a riser may extend the wellbore from the seafloor to the surface platform. One or more strings of casing withdiminishing inside diameters will be run inside of the conductor. Thewell may then be completed with a tubing string extending to the one ormore reservoir production zones. The annulus between the tubing and thesmallest diameter casing, i.e., the A-annulus, extends from theproducing zones to the surface. The surface barrier seals thetubing-casing annulus from the environment. The tubing may be landed forexample in a production packer located above the upper most productionzone to isolate the annulus from the producing zones. The tubing-casingannulus may extend thousands of feet from the surface to the productionpacker. The tubing-casing annulus may be utilized for example forgas-injection into the tubing to reduce the density of the fluid in thetubing to facilitate production to the surface. The tubing-casingannulus may be exposed to the surrounding formations via perforations orloss of casing integrity. In the case of failure of the surface annularbarrier, for example located at the wellhead, wellbore fluid in thetubing-casing annulus will be in communication with the environment.

In accordance to one or more embodiments, an annular safety valve isintegrated in the completion to provide an annular safety barrier in theupper completion. In accordance with embodiments, the annular safetyvalve provides one-way fluid flow from the upper annulus to the lowerannulus. In accordance to one or more embodiments, the annular safetyvalve provides one or more control line bypasses to operationallyconnect devices in the lower completion below the annular safety valveto surface control systems at the surface or in the upper completionabove the annular safety valve. In accordance to one or moreembodiments, the annular safety valve is not surface controlled.

FIG. 1 illustrates a well system 5 in which a polished bore receptacle(“PBR”) based subsurface annular safety valve (“ASV”), generally denotedby the numeral 10, may be incorporated and utilized. Annular safetyvalve 10 includes a one-way barrier valve 12 coupled with an annularbarrier 14. In accordance with embodiments, annular barrier 14 isreferred to as a polished bore receptacle (“PBR”) barrier 14. PBR 14provides a sealed annular barrier between the tubing and casing. Barriervalve 12 is illustrated as being located above PBR 14 in FIG. 1,however, as will be understood by those skilled in the art with benefitof this disclosure, barrier valve 12 may be locate below PBR 14. Barriervalve 12 provides one-way fluid flow in the direction from the uppercompletion or upper annulus across PBR 14 to the lower completion orlower annulus. In accordance to one or more embodiments, barrier valve12 is normally closed and actuated to the open position in response topressure in the upper annulus being greater than pressure in the lowerannulus. Similarly, barrier valve 12 is actuated to the closed positionin response to pressure in the lower annulus exceeding pressure in theupper annulus.

Well system 5 is illustrated as a gas lift completion that includestubing 16 that extends from an upper or surface barrier 18 into awellbore 20. A portion of wellbore 20 is completed with casing 22. Thetubing-casing annulus, generally denoted by the numeral 24, betweentubing 16 and casing 22 may be referred to as the A-annulus. Surfacebarrier 18, for example a tubing hanger, is depicted in FIG. 1 locatedat a water surface 26, for example at a platform, e.g., tension legplatform, or ship, positioned above a sea floor 28. Surface barrier 18may be located in the wellhead area. Reference to the surface of thewell is not limited to the sea surface or sea floor. Annular safetyvalve 10 is set in the upper completion and separates tubing-casingannulus 24 into an upper annulus 23 and a lower annulus 25. Lowerannulus 25 may be isolated from a production zone 7, i.e., reservoirformation, by a production packer 9.

Tubing 16 incorporates one or more gas lift valves 30 which are locatedin the lower tubing section 17 below annular safety valve 10 in wellbore20. For purposes of gas injection, well system 5 includes a gascompressor 32 located at the surface to pressurize gas that iscommunicated to tubing-casing annulus 24. The pressurized gas 34 iscommunicated from upper annulus 23 through annular safety valve 10 tolower annulus 25. The pressurized gas 34 is communicated from lowerannulus 25 into tubing bore 36 through gas lift valves 30.

One or more control lines 38 may extend from a surface system 40, forexample an electronic controller and or pressurized fluid source, todownhole devices, generally denoted by the numeral 42, located belowannular safety valve 10. Downhole devices 42 may include devices suchas, and without limitation to, pressure, temperature, and flow ratesensors 43, chemical injection valves 45, and flow control valves 47. Inaccordance to one or more embodiments, annular safety valve 10 providescontrol line bypasses from the upper completion or surface to the lowercompletion while maintaining an annular barrier. Control lines 38 mayinclude, without limitation, electrical and optic cables as well ashydraulic and chemical conduits.

Together, annular safety valve 10 and tubing 16 can serve as a primarybarrier to maintain well integrity. In the depicted embodiment, adownhole safety valve 44 is located in the upper section 15 of tubing 16to provide a vertical barrier through tubing bore 36. In this example,downhole safety valve 44 is a surface controlled subsurface safety valve(“SCSSV”) connected to the surface via a control line 38. Annular safetyvalve 10 serves as a safety barrier in A-annulus 24 in the event thatsurface barrier 18 is lost. Lower annulus 25 although located aboveproduction packer 9 in FIG. 1, may be in communication with formationfluids and pressure. For example, perforations or loss integrity ofcasing 22 may expose annulus 25 to the surrounding formation 46. In FIG.1, gas lift injection through lower annulus 25 may temporarilysupercharge formation 46.

With additional reference to FIGS. 2 to 4, polished bore receptacle 14includes a female PBR 48 integrated in casing 22 and a male PBR 50integrated in tubing 16. Female PBR 48 includes a smooth or honed boreformed on the inner surface of casing 22 and has a predetermineddiameter for sealing or mating with male PBR 50. Female PBR 48 isdepicted disposed above casing cross-over 27. Female PBR 48 may beconstructed as portion of casing cross-over 27. Tubing 16 may beanchored to casing 22 for example proximate to female PBR 48.

Depicted male PBR 50 (e.g., seal assembly) is an eccentric member havingone or more seal elements 52. Male seal assembly 50 is integrated withtubing 16 so that the tubing bore 36 extends through male seal assembly50. Bypass ports, generally denoted by the reference number 60, areformed longitudinally through male PBR 50, for example substantiallyparallel to tubing bore 36, to pass or form a portion of annular fluidconduit 54 and control lines 38 in the depicted embodiment. Barriervalve 12 is coupled with fluid conduit 54 to provide one-way fluidcommunication across PBR 14, i.e., upper annulus to lower annulus fluidflow. For example, ports 60 are formed through the thicker body portion58 of male PBR 50 between tubing bore 36 and seal elements 52. As willbe understood by those skilled in the art with benefit of thisdisclosure, annular safety valve 10 may be utilized in well systems 5that do not have gas injection.

With reference in particular to FIGS. 1-2 and 5-6, barrier valve 12 is aone-way valve providing fluid connection across polished bore receptacle14 from upper annulus 23 to lower annulus 25 through passage or conduit54. Although barrier valve 12 is illustrated located above PBR 14 inFIGS. 1 and 2, it will be understood by those skilled in the art withbenefit of this disclosure that barrier valve 12 can be located belowPBR 14 to provide fluid communication in the direction from upperannulus 23 to lower annulus 25.

In accordance to one or more embodiments, barrier valve 12 is located ina side pocket mandrel 56 integrated, i.e., connected, with tubing 16.Barrier valve 12 is disposed in pocket 62 (FIG. 6) to provide annulus toannulus fluid communication. Fluid, such as gas 34, flows from upperannulus 23 through port(s) 64 into pocket 62 and through barrier valve12 into conduit 54 and lower annulus 25. Side pocket mandrel 56 may notinclude a port between tubing-casing annulus 24 and tubing bore 36 orthe tubing bore may not be in communication with tubing-casing annulus24 through barrier valve 12. Side pocket mandrel 56 may be a single or adual pocket mandrel.

FIG. 7 illustrates a gas lift type barrier valve 12 in accordance to oneor more embodiments. Barrier valve 12 includes a reverse flow checkvalve 66 suited for barrier applications. For example, barrier valve 12is a barrier-qualified, reverse flow check valve that provides positiveseal between the lower annulus side and the upper annulus side. Inaccordance to one or more embodiments, barrier valve 12 hasmetal-to-meal seal surfaces without elastomers. Some embodiments mayhave elastomer seal surfaces. A non-limiting example of barrier valve 12is a NOVA 15-B type of gas lift valve available from Schlumberger.

In accordance to one or more embodiments, a surface control system isnot required for operation of annular safety valve 10. Barrier valve 12may be retrieved, for example via wireline or slickline, eliminating theneed to retrieve the completion to maintain the well integrity. If thepressure in lower annulus 25 exceeds the pressure in upper annulus 23,barrier valve 12 closes. Accordingly, barrier valve 12 fails safe closedif the surface barrier is lost. Annular safety valve 10 is insensitiveto setting depth. In accordance with one or more embodiments, barriervalve 12 may be eliminated for example by eliminating or pluggingconduit 54. For example, a dummy valve may be landed in pocket 62 toplug conduit 54.

A method in accordance to one or more embodiments is now described withreference to FIGS. 1-7. Casing 22 having a female polished borereceptacle 48 is set in wellbore 20. Tubing 16 is deployed landingintegrated male seal assembly 50 in the female polished bore receptacleforming an annular barrier 14 across a tubing-casing annulus 24, theannular barrier separating the tubing-casing annulus into an upperannulus 23 and a lower annulus 25. Male seal assembly 50 includes afluid conduit 54 extending substantially parallel to tubing bore 36.Barrier valve 12 is coupled with the fluid conduit to permit fluid, forexample gas 34, to flow from the upper annulus to the lower annulus.Fluid 34 is communicated from the upper annulus through the barriervalve and across the annular barrier in response to pressure in theupper annulus being greater than pressure in the lower annulus. Thebarrier valve is closed in response to the pressure in the upper annulusbeing less than the pressure in the lower annulus.

The foregoing outlines features of several embodiments of annular safetyvalves, systems, and methods so that those skilled in the art may betterunderstand the aspects of the disclosure. Those skilled in the artshould appreciate that they may readily use the disclosure as a basisfor designing or modifying other processes and structures for carryingout the same purposes and/or achieving the same advantages of theembodiments introduced herein. Those skilled in the art should alsorealize that such equivalent constructions do not depart from the spiritand scope of the disclosure, and that they may make various changes,substitutions and alterations herein without departing from the spiritand scope of the disclosure. The scope of the invention should bedetermined only by the language of the claims that follow. The term“comprising” within the claims is intended to mean “including at least”such that the recited listing of elements in a claim are an open group.The terms “a,” “an” and other singular terms are intended to include theplural forms thereof unless specifically excluded.

What is claimed is:
 1. A well system, comprising: a wellbore extendingdownward from a surface, the wellbore comprising a tubing deployed in acasing; an annular barrier disposed in a tubing-casing annulus of awellbore separating the tubing-casing annulus into an upper annulus anda lower annulus; and a barrier valve coupled with the annular barrier,the barrier valve permitting one-way fluid communication from the upperannulus to the lower annulus.
 2. The well system of claim 1, wherein theannular barrier is a polished bore receptacle.
 3. The well system ofclaim 1, wherein the annular barrier comprises: a female polished borereceptacle integrated in the casing; and a male seal assembly integratedin the tubing.
 4. The well system of claim 1, further comprising acontrol line passing through the annular barrier.
 5. The well system ofclaim 1, wherein the barrier valve is disposed in a side pocket mandrelintegrated in the tubing.
 6. The well system of claim 1, wherein thebarrier valve is located above the annular barrier.
 7. The well systemof claim 1, wherein the barrier valve is operated to an open position inresponse to pressure in the upper annulus being greater than pressure inthe lower annulus.
 8. The well system of claim 1, wherein the barriervalve is located in a side pocket mandrel integrated in the tubing; andthe polished bore receptacle comprises: a female polished borereceptacle integrated in the casing; and a male seal assembly integratedin the tubing.
 9. The well system of claim 8, further comprising gaslift valves located in the tubing below the annular barrier.
 10. Thewell system of claim 9, further comprising a control line extending fromabove the annular barrier through the annular barrier to a devicelocated below the annular barrier.
 11. An annular safety valve,comprising: a male seal assembly integrated in a tubing, wherein atubing bore extends through the male seal assembly; a fluid conduitextending through a body of the male seal assembly substantiallyparallel to the tubing bore; a female polished bore receptacleintegrated in a casing to receive the male seal assembly and form anannular barrier between the tubing and the casing; and a barrier valvein connection with the fluid conduit to permit one-way fluid flowthrough the fluid conduit.
 12. The annular safety valve of claim 11,wherein the barrier valve is disposed in a side pocket mandrelintegrated in the tubing.
 13. The annular safety valve of claim 11,wherein the seal assembly comprises a port formed longitudinally throughthe body to pass a control line across the male seal assembly.
 14. Theannular safety valve of claim 11, wherein the barrier valve is normallyclosed.
 15. A method, comprising: setting a casing in a wellbore, thecasing comprising a female polished bore receptacle; deploying a tubingin the casing, the tubing comprising a male seal assembly landed in thefemale polished bore receptacle forming an annular barrier across atubing-casing annulus separating the tubing-casing annulus into an upperannulus and a lower annulus, wherein the male seal assembly comprises afluid conduit extending substantially parallel to a tubing bore, and abarrier valve coupled with the fluid conduit to permit fluid flow fromthe upper annulus to the lower annulus; communicating a fluid from theupper annulus through the barrier valve to the lower annulus; andclosing the barrier valve in response to pressure in the upper annulusbeing less than pressure in the lower annulus.
 16. The method of claim15, wherein the fluid is a pressurized gas and further comprisinginjecting the pressurized gas from the lower annulus through a gas liftvalve into the tubing.
 17. The method of claim 15, further comprising acontrol line extending from the upper annulus through a body of the maleseal assembly to a device located below the annular barrier.
 18. Themethod of claim 15, wherein the barrier valve is located in a sidepocket mandrel integrated in the tubing.
 19. The method of claim 15,wherein the barrier valve is normally closed and the barrier valve isopened in response to pressure in the upper annulus being greater thanpressure in the lower annulus.
 20. The method of claim 17, wherein: thebarrier valve is located in a side pocket mandrel integrated in thetubing; the fluid is a pressurized gas; and further comprising injectingthe pressurized gas from the lower annulus through a gas lift valve intothe tubing.